This invention relates to transparent plastic articles such as light shades that contain a semi-transparent dye sublimation image preferably printed on a back surface thereof.
Various techniques are known for printing images on articles. For example, in U.S. Pat. No. 5,142,722, a process for applying images by transfer printing to furniture is described.
Heat transfer printing utilizes a heat transfer print sheet containing an ink image capable of transfer upon application of heat and pressure to a substrate usually containing a receptive coating layer.
In U.S. Pat. Nos. 4,059,471 and 4,465,728, plastic products receive a heat transfer image by using a polyolefin film between the dye transfer paper and a sheet of thermoplastic to avoid transfer of dye adhesive or carrier.
In U.S. Pat. No. 4,395,363, a process for applying an image using sublimation inks to a surface not normally receptive to such inks is disclosed. A primer coat which readily adheres to the surface is used with a binder layer adhered thereover. A clear layer or coating is applied, the layers being thermosetting and cured prior to receiving a dye sublimation ink transfer image.
Typically multiple layers are necessary to apply an image to an article, increasing cost and complexity. Further, care must be taken with plastics to avoid damage through the heat and pressure used in a heat transfer printing process.
The placement of images on a transparent article has several specific requirements. Distortion must be limited and image transfer must be exact, even and avoid bleeding of the dyes. High quality image transfer to transparent plastics and glass has not yet been satisfactorily achieved.
It is an object of the present invention to provide a method for transferring an image to a transparent article with a minimum number of steps.
It is a further object to provide high quality images on a transparent substrate at low cost.
It is a further object to provide a dye sublimation image on a transparent plastic or glass substrate with high clarity, definition and intensity so as to create an illuminable image.
It is yet another object to provide a transparent shade for a light fixture containing a semi-transparent image.
These and other objects of the present invention are achieved by a method for transferring a sublimation dye image to a transparent substrate comprising: providing a transparent substrate having a front surface and a rear surface; providing an image composed of transferable dyes; placing the image in contact with a surface of the substrate; transferring the dye image onto the substrate; and applying a light reflective coating to the rear surface of the substrate.
Preferably, the image is transferred to the rear surface, with the light reflective coating applied thereover. This light reflective coating also is preferably capable of diffusing light transmitted therethrough when the article is back illuminated to enhance perception of the image when viewed from the front surface. The transparent article may be made of glass or plastic.
Various printing techniques can be used to transfer a dye image to the substrate such as direct screen printing and pad printing but dye sublimation transfer printing is preferred, because such dyes can infiltrate into a surface to some depth, altering the substrate itself.
The image itself is preferably produced from transparent or opaque inks so that it is semi-transparent so as to allow light transmission therethrough. Application of a light diffusing coating may be used to distribute light evenly so as to illuminate the entire image when a light is placed behind the article such that the image is in essence projected therefrom. Utilizing this method, a photograph or other artistic image can be transferred quickly and cheaply to transparent plastic and when illuminated, provide a back illumination of the image which is particularly striking in clarity and quality.